ABSTRACT

This paper gives us the most complete version of the actual symbolic propositions used in Russell’s substitutional theory, as it was drafted for Principia Mathematica. Paper 12 is very much a working document, and Russell has left blank lines, which we have preserved, between parts of the text where he meant to create a division or perhaps thought that he might insert additional propositions later. 12 is revised from an earlier version, a fragment of which still survives but is not printed here.